A known particulate spreader incorporates a deflector that when activated impedes particulate material from exiting out one side of the spreader. Thus, any material dispersed in the spread pattern is impeded from spreading onto non-lawn areas, such as landscape beds, driveways, walkways, etc. In other words, the deflector simply deflects the dispensed material back toward the lawn area. A disadvantage of material dispersing systems that rely on such a deflector is that the amount of material dispersed (material flow rate) into the spread pattern remains the same whether or not a deflector is activated. Thus, if the deflector is activated the amount of material directed onto the lawn is more than the recommended amount since the deflected material also exits the side of the spreader opposite that of the deflector. This leads to over treatment of the lawn and to wasted product.